Automatic gear transmission



' March 21, 1939.

H. E. PEREZ AUTOMATIC GE ZAR TRANSMISSION Fil ed June 5, 1957 INVENTOR.v v Horacio EKPerez.

ATTORNEY.

. 56 Referring now to all the views simultaneously,

Patented Mar. 21, 1939 UNITED STATES PATENT OFFICE 3Clalms.

The invention relates to gear shift transmisslons particularly such as are used on automo- .tive vehicles, but may be put to other uses; It has for one of its principal objects to provide a gear transmission which is entirely automatic in its operation and through the instrumentality of which the different speeds, or gear ratios, are

automatically obtained in a continued sequence, a as the speed of the vehicle on which it is used is increased, so that the engine may be automatically kept at its optimum R. P. M. and thus develop its maximum torque at all times. This prevents stalling and results in greater fuel economy.

Another object is to provide a mechanism in which the actual gear shifting is eliminated,'in which the gears employed'are always in mesh with their co-acting members, and in which the gear ratio is always the most adequate at any given load or speed. ,A further object is to provide a gear transmission which is noiseless in its operation, which relieves the strain on the parts with which it is connected, which has no parts easily broken or apt to get outof order, which may be operated with but slight skill on the part 26 of the driver, which is suitable for all makes of automotive vehicles, which requires no changes or additions to the other standard parts of the motor vehicle, and which can be manufactured ing, as to the speed and proper gear ratio, de-

pending on the momentum of the moving vehicle;

,and which will absorb any sudden strain or. un-

35 even change of load on the engine,

attention from the driver.

These and various other objects and advantages will be readily understood from the following description and from the' accompanying 4o drawing of a preferred embodiment of the invention, in which, however, modifications may be made without departing from the scope of the appended claims. 'In. the drawing,

Fig. -l is a cross-sectional side elevation of the 45 gear-casing and its mechanism, with parts broken away to facilitate the description Fig. 2 is a cross-sectional end view of the casing control device" as seen from the engine and of the device'; I A so Fig. -3 is another cross-sectional end view-of the casing control device,

- the opposite end; and v 7 Fig.4 is a cross-sectional end view centrifugal friction member".

without showing the but as seen from the gear casing is shown at I0, the engine shaft at H, the drive shaft at l2, a stub-shaft at l3, and a cover, which gives access to the gear cas- I ing at M. A rotary drum I5 is provided with a front member l6 and a rear member l1. These 5 parts are secured to the drum by any suitable means. The drum is cylindrical and in it is contained the automatic gears as well as a centrifugal friction device all of which will be described later. Bearings l8 are formed in the end mem- 10 her l6 and in 'an intermediate member iii of the drum and in these hearings idlers 20 are free to rotate. Bearings 2i and 22 are formed respectively in the front and rear members of the drum. and in these bearings the shafts II and 15 I3 rotate, while the shaft l2 rotates'ina bearing 23 formed directly in the gear casing. The drum is oil-tight and completely filled with lubricating oil.

The engine shaft H is pr'pvided with a, reduced 20 portion 24 which rotates in a bearing 25 formed 7 in the end of shaft I3. Each of the idlers 20, of which three or more may be used, are made in one piece and each consists of a large gear 26 and a smaller gear 21. All the idlers are ar- 25 ranged and operated as planetary gears around gears 28 and 29 keyed respectively to shafts H and I3. A rotating member 30 is also keyed to the shaft l3 and contained within a chamber 3| formed in the drum. This rotor will be described 30 later.

The bearings 2| and 22 in which the shafts H and I3 rotate is in turn rotatably mounted in bearings 32 and 33 formed in the gear casing. These bearings as well as the bearing 23 are 35 provided with bearings of the antiefriction type. The shaft I3 is preferably formed in one piece with a gear 3 and on the front end of this gear a clutch member 35 is formed. Another gear 36, likewise provided .with a clutch member 31, is rotatingly mounted on the driving shaft l2. The gear 34 meshes with a gear 38 rigidly mounted on a counter-shaft 39. On the other end of this counter-shaft a smaller gear 40 is rigidly mounted'which, through an idler 4i, meshes with the gear 36.

A bushing 42 is mounted on the dashboard 43 and a tubing 44 is connected between this bushing and an'opening 45 in the gear casing cover II. A flexible 'metal cable 46 is slidingly mounted in the tubing and one endof this cable is connected to an operating knob 41, while the other end is connected to a rod 48, which is-pivoted to a lever- 49 rotatingly mounted on a shaft 50 in the gear casing. A shorter lever 5! is cast integrally with the lever 49 and is pivoted to a link 52, which in turn operatesa yoke 53 rigidly mounted on a shaft 54 which slides in bearings 55 and 56, formed in the gear casing. The yoke drives the sliding clutch-member 51 which is adapted to engage with the clutch members 35 and 31 formed, respectively, on the gears 34 and 36;

To lock the yoke in the desired position, a

plunger 58 is employed. This plunger is actuated by a spring 59 which engages in notches 60 cut in'the shaft 54. The clutch member 51 rotates with the shaft 12. It will readily be seen that by manipulating the knob 41 the gears may be placed in neutral,as shown in Fig. 1, or in forward or in reverse as desired. .When the clutch part 51 is engaged with the clutch part 35 it will impart forward motion to they car, and

when engaged in clutch part 31 it will impart reverse motion. 4

The rotating member 30 is shown in detail in Figs. 1 and 4. As previously stated it is keyed to the shaft l3 so as to rotate with this shaft and is contained within the chamber 8|, formed in the drum I5. Four centrifugal weights 6 l' are mounted in recesses formed in the rotor and are free to slide in these recesses. The shapes of the recessesand the weights are plainly shown in Figs. 1 and 4. As the shaft l3 and member 30 rotate together, the centrifugal force will cause the weight 6| to be forced against the walls of the drum and, as the friction increases with the speed of rotation, they will finally cause the drum to rotate at the same speed as the shaft. By virtue of this friction, the inherent tendency of the drum to rotate, because of its fly-wheel action and because of the friction with shafts I I and I3 is augmented and made positive as the speed of the vehicle increases.

Figs. 2 and 4 show the drum control-device in detail, but reference is also made to Fig. 1. Another drum 52 is rigidly secured to the gear casing so that it cannot rotate. The front member 15, of the drum I5, is provided with a forwardly extending, annular ring 63 and on the outside of this annular ring, a plurality of. angular notches 64 are formed. In these notches rollers 65 are inserted, as plainly shown in the views. These rollers allow the drum'to turn freely in the same direction as the engine shaft, as indicated by the arrows 86, as shown in Figs. 2 and 3, but will lock the drum l5 to the drum 62 if the drum l5 begins to turn in the opposite direction.

A mechanically operated brake is contained within the drum 82 and the annular ring 03. It consists of two brake shoes-l1 which are hinged on a'stud 68 secured on the drum, as plainly shown in Fig. 1. Y The brake shoes engage against studs 1| and 12, likewise secured on the drum 52. The bell-cranks. 59 and 10 are actuated by a rod 13, while the brake shoes are normally held in their inactive positions by a tension spring 14 which is attached to the extremeends of the shoes.

As previously said the drum is allowed to rotate freely in the same direction as the shaft H,

nected between the arm 15 and a lever 18 which.

is formed integrally with another arm 19 to which the upper end of the rod 12 is connected. Thus when the foot brake 15 is depressed the arm 15, through the spring 11, actuates the lever 18 and consequently, through the arm 19 and rod 13,

actuates the bell-cranks 59 and 10, thus forcing the brake shoes 61 against the annular ring Cl and slowing down, or stopping, the rotation of the drum.

The tension of the spring 11 is sufficient to completely stop the drum before the spring is perceptibly stretched. The rod 80, usually connected to the wheel brakes, is slotted at its front end, as shown at 8|, so that the brake pedal 16 may partly be operated before the wheel brakes are actuated. Thus the rotation of the drum may be slowed down or stopped without actually setting the wheel brakes. The advantages of this arrangement will be made clear as the operation of the entire mechanism is explained.

The transmission operates in the following manner: In Fig. l the transmission is shown in neutral position and is assumed to have been l disconnected fr6m the running motor by the conidlers, in turn are in mesh with the gear 25, the I turning of the shaft I I must result in one of two mdtionsf either gear 29 together with the shaft l3, gear 34, clutch part 35, clutch part 51 and shaft l2 will rotate in the same direction as engine shaft H (at a lower speed of course depending upon the gear ratio used in the idlers). or. the idlers 20 will rotate and simultaneously move in the opposite direction. In the latter case the entire revolvingdrum 15 must necessarily turn with the'idlers 20, but will be checked in itsreverse motion by the rollers 65 as previously explained and illustrated in Figs. 2 and 3. Therefore, the engine power must be transmitted as follows: From engine shaft II and gear 25,

to the gears 26 of the idlers, from the smaller gears 21 of the idlers, to the gear 29 and hence,

through the stub shaft II and through the clutch.

creased in speed but increased in power. The

motor is now in low.

As the speed of the engine'is accelerated and the increasing momentum of the car diminishes the load, the revolving drum will tend to rotate because of its stored energy. This tendency is augmented by the friction at the bearings of the idlers as their rotation will slow down in direct proportion to the turning of the drum. Besides. friction of engine shaft H and of the drum at its long bearings 2| and 22, as well as the friction of the shaft I3, will tend to turn the drum with them. As shaft l3 turns, the rotary member III will also turn and the centrifugal force thus developed will force the sliding weights 6| against the revolving .casing so that it will finaly turn at the same speed as the shaft l3; which is connected by the clutch mechanismto shaft l2. When this occurs the idlers must have stopped their rotation and therefore the entire system is turned as a single.

unit. The gear is now in direct drive".

Itis obvious that in making this changefrom V. 2,151,151 "low and into direct drive, the mechanism must have passed through all ratios of power and speed. Therefore, if the gear ratios are properly chosen, the mechanism will, as the speed of the vehicle increases, automatically change from ,low into "direct drive" through a countless series of gear ratios, gradually passing from one into the other in a continued sequence, without breaks or jerks and as speedilyas the momentum of the vehicle will permit. At first it may seem impossible to obtain different gear ratios with the same set of gears but this is made possible by the rotation of the drum I5 together with the simultaneous slowing'down of the idlers 20. i

Any sudden increase in the load will cause the drum to slow down and so, the shock is automatically absorbed in the transmission and not passed on to the motor. This prevents stalling because the ratio immediately and automatically becomes adequate to any given change in power. load or speed, whether this change is gradual or sudden.) Thus this automatic gear transmission,

although under positive control at all times, has

enough inherent flexibility to absorb and to Ed? just itself to all sudden jerks and strains.

Whenever it becomes necessary to slow down' the vehicle, the brake pedalmay be depressed slightly and by virtue of the slotted link 8| in the brake rod 80, the wheel brakes will not be affected at first. However, since the tension spring 71 has sufficient strength to pull, it will be transmitted to the lever 18 which will, through arm I9, lift the rod 13 and apply the brake shoes 61 against the annular ring 63. As'this brake has no lining it cannot lock the drum suddenly, but will slow it down gradually. As the speed of the drum diminishes the idlers 20 will simultaneously begin to rotate allowing for the difierence in speed between the shaft ll, drum l5 and drive shaft I2. The power isthen transmitted through the gears and the vehicle has been slowed down by gradually increasing the gear ratio so that as the speed is decreased, the power of the motor is relatively increased. This may be used to advantage in going down hill when the car may be slowed down without using the wheel brakes. Another advantage is the fact that the car will gradually go into low just before the brakes are applied, thus preventing skidding on wet pavements. Moreover, as the vehicle slows down the motor can stay at the optimum R. P. M, thus developing its greatest power. 7

"Reverse" is obtained by drawing the knob ll all the way out. ,Thus causing the clutch part 57, to engage with the clutch part 3'! on the gear 36. a The power is now transmitted to the shaft l2 through. gears 34, 38, 40, El, 36 and through the clutch tosh'aft l2.

From the foregoing it will be evident that this invention remedies many of the defects and disadvantages found in present gear shift mechanisms. It eliminates the necessity of shifting and also reduces to a minimum the number of times the clutch must be used, thus removing one. of the difficult operations now required of the driver. It greatly reduces the number of operations required for-starting a car, which is important in saving of labor and in avoiding fatigue from the repeated starting and stopping in driving. 1

As the gears are always in mesh there is n grinding of the gears, nor jerking of thecar. The car is always in proper gear ratio for any given load or speed. There is no stalling, no

sudden extra load on the engine or the gears, as the transmission is flexible enough to absorb any sudden or uneven phange in the load and to adjust itself quickly and automatically to any given speed. .There is no "rolling as the car is always under positive control. Furthermore, this device does not occupy any larger space than the ordinary, standard, gear-shift mechanism. It requires no changes in the other parts of the vehicle, can be adapted to allstandard makes of vehicles, and it requires no special skill on the part of the driver.

While the mechanism has been illustrated and described in connection with a motor vehicle, I do not thereby wish to confine it to such use only, but intend to use it in connection with any other device on which it may be used to advantage.

Having described the invention and its objects, what I claim as new and wish to protect by Letters Patent is:

1. In atransmission of the type described hav ing a gear casing, a driving shaft and a driven shaft, a stub shaftunterposed between the driving shaft and the driven shaft and free to rotate independently of said shafts, a cylindrical drum rotatingly mounted on the driving shaft and the shaft, another gear mounted on the end of the stub shaft, said gears connected by a plurality of idlers so proportioned as to impart diiferent speeds to the stub shaft and the driving shaft, the idlers rotatlngly mounted in bearings formed in the drum, a rotary member rigidly secured to the stub shaft and rotating in a chamber formed in the rotating drum, a plurality of centrifugal weights slidingly mounted in said rotary member and adapted to engage with the inner circumference of the chamber to frictionally engage the drum and cause it to rotate with the stub shaft, a brake drum formed in the driving shaft end of the drum, brake shoes mounted in the gear casing for engagement with the inside of said brake drum, and means for actuating said brake shoes connected with the brake pedal of the vehicle on which the transmission is used.

2. In a transmission of the type described having a gear casing, a driving shaft and a driven shaft, a stub shaft interposed betweenthe driving shaft and the driven shaft. and free to rotate independently of said shafts, a cylindrical drum rotatingly mounted on the driving shaft and the stub shaft, said drum also supported in bearings formed in the gear casing in a fixed position axially, a gear rigidly mounted on the driving shaft, another gear mounted on the end of the stub shaft, said gears connected by a plurality of idlers so proportioned as to impart different speeds'to the stub shaft and the driving shaft, the idlers rotatingly mounted in bearings formed in the drum, a. rotary member rigidly secured to the stub shaft and rotating in a chamber formed in the rotating drum, a plurality of centrifugal weights slidingly mounted in said rotary member and adapted to engage with the inner circumference of the chamber to frictionally engage the a brake drum formed in the driving shaft end of the drum, brake shoes mounted in the gear casing for engagement. with said brake drum, means for actuating said brake shoes connected with the brake pedal of the vehicle on which the transmission is used, and means associated with said brake pedal which will enable said brake shoes to be set before the wheel brakes of the vehicle are actuated.

3. In a transmission of the type described having a gear casing, a driving shaft and a driven shaft, a stub shaft interposed between the driving shaft and the driven shaft and free to rotate independently of said shafts, a cylindrical drum rotatingly mounted on the driving shaft and the stub shaft, said drum also supported in bearings formed in the gear casing, a gear rigidly mounted on the driving shaft, another gear mounted on the end of the stub shaft, said gears connected by a plurality of idlers so proportioned as to impart different speedsto the stub shaft and the driving shaft, the idlers rotatingly mounted in bearings formed in the drum, a rotary member rigidly secured to the stub shaft and rotating in mission is used.

a chamberformed in the rotating drum, a plurality of centrifugal weights slidingly mounted in said rotary member and adapted to engage AHORACIO E. PEREZ. 

